Process for the production of colored images by photography



Patented Mar. 12, 1940 UNITED STATES PROCESS FOR THE PRODUCTION OF COL- ORED IMAGES BY PHOTOGRAPHY Henricus Jacobus Charles Tendeloo, Wageningen, Netherlands, assignor to Shell Development Company, San Francisco, Calif., a corporation of Delaware No Drawing. Application October 11, 1937, Se-

rial No. 168,436. In the Netherlands October 21, 1936 15 Claims.

The present invention relates to a process for the production of colored images by photography, said colored images being produced in the film and in other light-sensitive layers, such as those on printing papers.

The introduction of sound and color into photography can be considered as very desirable improvements in the photographic art. Of these improvements the use of sound in conjunction with photography has been well developed while the introduction of colorhas been confined to a large extent to amateur use. Of the subtractive color processes developed, mention should be made of the Technicolor, Gaspar, Kodachrome and Agfa processes. These processes constitute technically improved processes basedupon old ideas and have in general the disadvantage of requiring manifold and exacting processing and complicated and expensive methods of copying.

Since the ease of copying the films is of such paramount importance in the motion picture industry most of the above mentioned processes have not found extensive use in this field.

According to the present invention use is made of a light-sensitive compound which upon exposure to light of the proper wave length and if desirable development, liberates a fragment, ion or radical which remains to yield an image which corresponds in color to the natural color of the photographed object.

It is known that certain light-sensitive compounds upon being exposed to light of the proper wave length and to such development as may be desirable, break up, decompose, ionize or in some manner become separable into simpler materials. Thus, for example, the image of the ordinary black and white photograph is ascribed to metallic silver.

I have found thatthere are compounds which break down upon exposure into two fragments, one of which is colored or becomes colored after developing and the other of which may be selectively removed by suitable solvents. I also found that many of these colored fragments behave quite differently than the original unexposed compounds, thus allowing the selective removal of any unexposed compounds. Likewise, I have found that by the proper choice of radicals it is possible to produce colored images of almost any color by photography using these fragments to produce the colored images. Further, I have found that it is not essential that the fragment be colored per se, but that it is likewise possible to use such compounds as upon exposure and if desired development, yield uncolored fragments which upon a simple treatment yield a stable colored image.

An example of a compound to be used in this manner is a metal salt of an oxamic acid, such as Ag, Cr, Hg, or Fe salt of o-nitro oxanilic acid. After exposure and development o-nitro aniline is formed, which is yellow. The metal liberated on exposure and the non-exposed salt are removed by a suitable bath, e. g. a KCN bath when Ag has been used as metal.

According to the present invention, any, preferably organic, dye compound which is lightsensitive and which after exposure and such development and fixation as the case may require leaves in the emulsion layer a colored ma terial or a material capable of yielding a color upon a simple treatment, may be used. It is also possible to use a light-sensitive salt, which onexposure and such development as may be desired, decomposes into a fragment which is insoluble in the baths to be used and possesses per se, or upon a simple subsequent treatment,.

the desired color and a readily removable residue. It is essential that the color-forming material liberated upon exposure to light and developis that of basic-acting dyes coupled'with a polybasic acid, such as oxalic acid, and derivatives thereof.

The basic-acting dye can be coupled with the oxalic acid by means of a NH: group of the dye, whereby the oxalic acid derivatives of the general formula RINRZCO.COOX and homologues thereof are obtained, in which contains the dye-carrying substance, and R1 represents an organic dye-carrying radical, R2 represents hydrogen or an organic radical and X represents a light-sensitive cation. The acids may be prepared: for example, by causing the dye-carrying compound RrhsN'i-i to act on ethyl oxalate. After saponiflcation of the ethyl ester obtained, the acid all... 121

is formed. when R2 represents hydrogen, the acid R1NH.CO.COOH is formed.

Thus, for example, the salts,

(producing a red color) swim-..

0 N ,(producingared color) 0 0 H H 0 0 g g I u xo-- --NQQNC -ox Nos 0: I (producing a yellow color) and the oxamine derivative of on I on =N N=N NE, on, 7 OH;

(producing a blue color) may be advantageously used.

A basic-acidng dye containing an OH-group can also be coupled with the polybasic acid by means of the OH-group, an ester being then formed of the general formula in which B- represents the dye-carrying sub- 4 stance and x a light-sensitive cation. The reaction is then as follows:

B-OH-l-HOJL--OH n-oJzJl-orwmo in which 3-01! is the basic-acting, OH-containing dye.

The emulsions may be sensitized to light of given wave lengths by the usual known methods. Different degrees of light sensitivity may also be attained by the use of isomeric compounds.

suitable for the particular dye-base.

In order to produce multicolored images, I prefer to apply the emulsions, each sensitized to a particular colored light, in layers on a suitable emulsion-carrier. In such cases where the sensitizing agents in two adjacent emuision'layers react to their mutual detriment, it is possible to eliminate this undesirable reaction by using as a separator a layer of gelatin or other suitable areas material. This separator-layer may contain a removable dye if desired, in which case it acts as a color filter. In some cases it is possible to mix the emulsions, each sensitive to a particular color, in which case the mixture may be applied to a suitable carrier and ripened.

As illustrative of a suitable manner in which my invention may be applied, I offer the following examples, which, it is to be understood, are not to be considered as limiting the scope of the invention as regards kind or proportions of materials used nor mode of execution:

Example 1 To one volume of an aqueous 8% gelatine solution at about 30 0. there was added one volume of a 1% solution of an oxamine derivative of mononitro benzidine, viz.

will-..

in water to which a small amount of NHAOH had been added to aid the solution. To this was added 0.1 volume of a 0.01% thiosinamine solution in water and the whole thoroughly mixed. To thissolution there was added,- during intensive stirring a little more than the equivalent amount of N AgNOs solution (in all about 0.075

volume of AgNO; solutiomp The emulsion was poured over a suitable carrierand dried. The fllm thus prepared was exposed and then treated in a bath consisting of a 3% ammonium persulfate solution to which there had been added a few drops of a 3% KCN solution. The exposed portion remained behind as a red color.

Example 2 practically chloride-free by washing it with water.

The gelatine mixture was then mixed in the dark, while stirring, with 1 cm. AgNO; solution of 0.1 normal, and spread out on photographical paper treated with barytes. On 150 cm. paper about 3 cm; emulsion was used. The emulsioncarrying paper thus obtained was dried in a dark drying tunnel.

The dry paper was exposed diffuse daylight. After about 20 minutes already a shade of' color 1 hours and the exposed paper was then treated for about 5 minutes in a one per thousand solution of KCN in water, whereupon it was washed with fresh water for about half an hour and then dried. A red picture was thus obtained.

Example 3 A light-sensitive paper with the silver salt of 2.2-dinitro-benzidine-dioxamic acid was produced in the manner described in Example 2, and thereafter exposed and treated in the same way. A yellow-colored picture was obtained.

Example 4 A light-sensitive paper with the silver salt of o-nitro-oxanilic acid was produced in the manwas seen. The exposure was continued for about ner described in Example 2, and after exposure Example A light-sensitive paper with the silver salt of p-nitro-oxanilic acid was produced and treated as in Example 4. A yellow picture was obtained after exposure.

Emmplle 6 A light-sensitive paper with the NH4-salt of 2.2'-dinitro-benzidine-di-oxamic acid was produced in the sameway as the silver salt in Example 3. After exposure the exposed material was only washed with water, whereby the unexposed part was washed out. A yellow-colored picture was obtained.

While I have described my invention in a detailed and comprehensive manner and provided specific examples of executing the same, it is to be understood that no limitations are intended other than those imposed by the scope of the claims.

I claim as my invention:

1. A light-sensitive photographic layer suitable for the production of colored images containing a light-sensitive salt of a substituted oxalic acid in which a carboxyl group has been coupled with an amino group of an organic dye, which salt upon exposure and such development as may be desirable is separable into a relatively soluble cation-containing fragment removable by solution, as is the unexposed salt, and a relatively insoluble organic fragment which remains to yield a colored image.

2. A light-sensitive photographic layer suitable for the production of colored images containing a light-sensitive metal salt of a substituted oxalic acid in which a carboxyl group has been coupled with an amino group of an organic dye, which salt upon exposure and such development as may be desirable is separable into a relatively soluble cation-containing fragment removable by solution, as is the unexposed salt, and a relatively insoluble organic fragment which remains to yield a colored image.

3. A light-sensitive photographic layer suitable for the production of colored images containing a light-sensitive silver salt of a substituted polybasic acid in which a carboxyl group has been coupled with an amino group of a dye, which salt upon exposure and such development as may be desirable is separable into a relatively soluble cation-containing fragment removable by solution, as is the unexposed salt, and a relatively insoluble organic fragment which remains to yield a colored image.

4. A light-sensitive photographic layer suitable for the production of colored images containing a light-sensitive metal salt of a substituted oxalic acid in which a carboxyl group has been coupled with an amino group of an azo dye, which salt upon exposure and such development as may be desirable is separable into a relatively soluble cation-containing fragment removable by solution, as is the unexposed salt, and a relatively insoluble organic fragment which remains to yield a colored image.

5. A light-sensitive photographic layer suitable for the production of colored images containing a light-sensitive metal salt of a substituted oxalic acid in which a carboxyl group has been coupled with an amino group of a nitro dye, which salt upon exposure and such development as may be desirable is separable into arelatively soluble cation-containing fragment removable by solution, as is the unexposed salt, and a relatively insoluble organic fragment which remains to yield a colored image. z

6. A light-sensitive photographic layer suitable for the production of colored images containing a light-sensitive metal salt of a substituted oxalic acid in which a carboxyl group has been coupled with an amino group of a bis-azo dye, which salt upon exposure and such development as may be desirable is separable into a relatively soluble cation-containing fragment removable by solution, as is the unexposed salt, and a relatively insoluble organic fragment, which remains to yield a colored image.

7. A light-sensitive photographic layer suitable for the production of colored images containing as an image and color-forming agent a light sensitive silver salt of a substituted oxalic acid in which a carboxyl group has been coupled with an amino group oi an azo dye.

8. A light-sensitive photographic layer suitable for the production of colored images containing as an image and color-forming agent a lightsensitive silver salt of a substituted oxalic acid in which a carboxyl group has been coupled with an amino group of a nitro dye.

9. A light-sensitive photographic layer suitable for the production of colored images containing as an image and color-forming agent a lightsensitive silver salt of a substituted oxalic acid in which a carboxyl group has been coupled with an amino group of a bis-azo dye.

10. A light-sensitive photographic layer suitable for the production of colored images containing as an image and color-forming agent, the compound Hm N=N 11. A light-sensitive photographic layer suitable for the production of colored images containing as an image and color-forming agent, the compound Y 1 u l I I ll Ago-d-o- N N-d-c-O-A;

12. A light-sensitive emulsion suitable for producing colored images by photography and containing as a light-sensitive agent a metal salt of a substituted oxalic acid in which a carboxyl group has been coupled with a polar group of a dye, which salt upon exposure and such development as may be desirable is separable into a rela-- with an amino group of an organic dye, whichcompound upon exposure and such development as may be desirable, is separable into a relatively soluble fragment removable by solution, as is the unexposed compound, and a relatively insoluble fragment which remains to yield a colored image.

14. A light-sensitive photographic layer suitable for the production of colored images containlng a,member selected from the group consisting of light-sensitive dicarboxylic acids and talning a member selected from the group consistlng oi light-sensitive oxalic acids and lightsensitive oxalic acid metal salts in each'ot which a carboxyl group has been coupled with an'amino group of an organic dye, which compound upon exposure and such development as may be desirable is separable into a relatively soluble tragment removable by solution, as is the unexposed compound, and a relatively insoluble fragment which remains to yield a colored image;

HENRICUS JACOBUS CHARLES TENDELOO. 

